telomere shorter, so they live shorter for one. The other reason is that cloning animals is really a trial and error thing, like there were more than 300 unsuccessful attempts or something before dolly was born. So the animal might have other developmental problems.

Taking used and abused DNA out of an adult somatic cell and sticking into a bright shiny new embryo, albeit enucleated, and having it come out viable is a miracle. As long as the DNA wasn't too abused and used, the clone will be viable, but it might have all the mutations that the new DNA repair system just couldn't fix. Most cloned animals have developmental problems later on, and develop diseases fairly quickly. Thus, no they don't live longer than the original.